As you can see, the consumption of red meat has actually fallen over the past several decades while leaner poultry increases in popularity.

However, if we are looking for a possible dietary villain, then soybean oil consumption has grown by a huge magnitude.

It is in almost everything we eat; not only as a cooking oil but also in salad dressings and processed foods.

And studies show that it is “more obesogenic and diabetogenic than fructose” (2).

The (Waist) Expanding Role of Soybean Oil in Obesity

Vegetable oils were almost unheard of in the early 20th century. In contrast, they are everywhere these days.

Specifically, domestic consumption of soybean oil has more than quadrupled from 1,652,000 tons in 1964 to 6,576,000 tons as of 2016 (3).

At the same time, there has been an explosion in obesity and diabetes. And here are some possible reasons as to why;

An animal study compared the impact of a diet high in soybean oil to high fructose and coconut oil diets. The mice fed large amounts of soybean oil had significantly more weight gain, diabetes, and insulin resistance. Additionally, the soybean oil diet upregulated cancer, inflammation and obesity-related genes (2).

Another animal study fed mice a high-fat diet of either soybean, olive oil, MCT oil, peanut oil, or tea oil. Following the study, body weight and body fat were significantly higher in the soybean oil group compared to all others. Also, the soybean oil group had visible fatty liver disease—the MCT, olive oil, and tea oil mice did not (4).

In a study comparing butter and soybean oil, fat oxidation increased in the group fed butter. In the soybean fed group, subjects showed an inability to oxidize fat while resting (5).

Key Point: Animal studies show that soybean oil uniquely causes obesity and diabetes compared to other fats. Based on the obesity crisis, perhaps the same is true in humans.

2. Soybean Oil Leads to Inflammation

The chart below shows the nutrition facts per one tablespoon of soybean oil (1);

Nutrient

Amount

Carbohydrate

0g

Protein

0g

Fat

13.5g

Saturated Fat

2.1g

Monounsaturated Fat

3.1g

Polyunsaturated Fat

7.8g

Omega-3

917mg

Omega-6

6807mg

Vitamin E

6% RDA

Vitamin K

31% RDA

As shown above, soybean oil is predominantly a source of polyunsaturated fats (PUFA).

The omega 6 to 3 ratio is approximately 7.4: 1.

When you consider that soybean oil is in almost everything, it’s not hard to imagine someone having 4 or 5 tablespoons per day.

In other words, about 30 grams of omega-6 and only 4 grams of omega-3. A huge difference.

Importance of Balancing Omega-6 and 3

Although both omega-3 and omega-6 are essential fatty acids, we should consume them in relative balance.

Due to the excessive amount of vegetable oils in the modern diet, people are eating way too much omega-6 and nowhere near enough omega-3.

Notably, estimates place the modern diet as having a ratio of 20:1 or higher (6).

Omega-6: Healthy Until It’s Not

Omega-6 is an important fatty acid that is pro-inflammatory in nature, and this is a good thing.

For instance, some inflammation in the body is necessary for healing cuts and wounds.

However, in excessive amounts it causes our body to stay in an inflammatory state — and chronic inflammation is a known risk for the majority of illnesses (7).

Some harmful effects of too much omega-6:

As omega-6 competes with omega-3 for uptake into our cells, too much omega-6 means a deficiency of anti-inflammatory omega-3 (8).

Studies show that a lower dietary omega-6 to omega-3 ratio reduces inflammation and mortality risk from heart disease (9).

Chronic diseases such as diabetes, obesity, IBD and arthritis all have associations with increased omega-6. Imbalances in the omega 6 to 3 ratio have likely increased the prevalence of multiple inflammatory, disease-causing processes (10).

That said, this is not a problem unique to soybean oil. Other oils rich in polyunsaturated fats such as grapeseed oil have the same problems.

Key Point: Soybean oil is in almost everything and significantly contributes to the excessive amounts of omega-6 in our diet. As a result, harmful effects of inflammation are becoming the norm.

3. Soybean Oil Can Increase the Risk of Cardiovascular Disease

Despite the food industry’s message that soybean oil is ‘heart healthy,’ most people with interest in nutrition know better.

In fact, the science shows it is probably the very opposite; soybean oil is unhealthy and likely damages the heart;

Compared to saturated fats, soybean oil is very unstable as it is predominantly a polyunsaturated fat. Vegetable oils are susceptible to oxidation when exposed to heat, which can cause their fats to oxidize. Consuming oxidized fats has a detrimental impact on blood pressure and cholesterol and also increases inflammation (11).

An unbalanced over-production of omega-6 in the body has a strong association with atherosclerotic diseases (cardiovascular disease) (12).

Existing data for the health benefits of soy is “inadequate and inconsistent,” and there is concern that widely consuming soy products may cause harm to the public (22, 23, 24).

Key Point: Soy mimics the effects of estrogen and may cause a range of damaging impacts in the body. In particular, there are strong concerns regarding soy consumption and fertility issues.

7. Heated Soybean Oil is Likely Carcinogenic

Due to the unstable composition of soybean oil, exposing it to heat is a terrible idea. In contrast to saturated fats, omega-6 vegetable oils are very prone to oxidation.

However, the problem is that restaurants and fast food chains around the world even use soybean oil for deep drying. Using soybean oil at high heat virtually guarantees a large dose of oxidized fats (25).

Studies on Heating Oils and Carcinogens

Trans fats, toxic aldehydes, and various other “volatile compounds’ form when frying soybean oil at high heat (26, 27).

Heat degrades omega-6 vegetable oils into toxic compounds that have “properties that often signal carcinogenesis” (28).

One study fed female rats either soybean oil or ghee; the soybean oil group had higher tumor incidence, larger tumor size, and a more rapid onset of cancer (29).

In animal studies, soy oils oxidized through heating cause oxidative stress and also increase the blood pressure in subjects (30).

Key Point: Soybean oil is full of polyunsaturated fats which can easily oxidize. Oxidation creates harmful compounds that have dangerous effects in our body.

8. Made From GMO, Glyphosate-Sprayed Soybeans

The industrial giant Monsanto’s glyphosate is one of the most controversial topics in the health world.

It is a chemical pesticide which the world health organization label as “probably carcinogenic to humans.” Glyphosate has links to a variety of modern, chronic diseases including cancer and neurological diseases (31, 32, 33, 34).

Over 90% of soybeans are genetically modified (GMO) for resistance to glyphosate. This modification allows the plant to survive being sprayed with pesticides and herbicides (35).

A recent study investigated the composition of natural soybeans versus GMO soybeans treated with glyphosate. The results showed that (36);

The soybeans not treated with glyphosate all had better nutritional profiles than the GMO beans.

Glyphosate-sprayed soybeans contain residual amounts of the chemical.

GMO soybeans are responsible for the vast majority of soybean oil. Many people have a concern that these scientifically modified beans may damage health.

I bought a multivitamins and minerals supplement and on the box says antioxidant. Then I read the ingredients and the first ingredient is soybean oil and thought something is wrong here. Why those laboratories have to put soybean in multivitamins and minerals supplements? Thanks for the info!

Certain types of vitamins are fat-soluble, which means that they need a source of fat for proper absorption. In truth, the amounts in capsules are minimal, and it is better to take them alongside a meal with a higher amount of healthy fats.

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16 days ago

Guest

tracy

wow – even the low carb foods all have soy bean oil – so frustrating– great article, thanks

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3 months ago

Guest

Kris Grauel

I was prompted to read this article because I bought some tuna with soy bean oil in it by mistake. I will make sure going forward that whenever I buy tuna it is in water only.

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4 months ago

Guest

Cindy

As they point out, it’s hard to avoid. High time for the public to demand our food no longer be contaminated with this toxic industrial oil. There seems to be very little awareness out there of how it is put in just about everything. It makes great candles though…:)

Indeed – most packaged food seems to contain this (alongside sugars and flour!)

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7 months ago

Guest

Denise

Hi. I was wondering what might make dogs develop tumors quickly. My dog’s diet only consists of dog food and water. He’s a 12 year old Miniature Schnauzer and has started developing many fatty tumors. I have only been giving him filtered water and am now looking to the food I buy and looking even more closely to what’s in it. I feed him Castor & Pollux brand which includes 3% Omega-6 and saw in your article this was known to increase tumors in animals consuming high Omega-6. I was wondering if there was connection and if Soybean Oil in… Read more »

I’m sorry but I don’t know much about pet food – it would be better to ask your vet about this.

As for the soy milk, sorry to hear about your side effects – if you can’t drink regular dairy, almond milk or coconut milk could be good alternatives. The best food sources of vitamin D include fatty fish like salmon and mackerel, eggs, mushrooms, cod liver oil.

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7 months ago

Guest

Javier

Obesity in the US has everything to do with hydrogenated vegetable oils (forbidden in Europe and only very recently forbidden in the US too), and using fructose syrup instead of natural sugar. It has nothing to do with using vegetable oils. The vegetable oil market in the US is extremely deceptive

(Partially) hydrogenated vegetable oils don’t really have a unique effect on obesity. They are terrible for health, sure, but they are not behind rising obesity rates.

Obesity rates are rapidly rising across the EU (especially Western Europe) and the US, and it is mainly due to too much non-satiating industrially processed foods in too high quantities.

There isn’t really one ingredient that causes obesity – it is our overall diet and lifestyle. That said, animal studies show soybean oil to be obesogenic, and no oils are particularly nutrient-dense, so it certainly doesn’t help given the quantities it is consumed in.

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8 months ago

Guest

A. K.M Mohiuddin

Thanks for the valuable information which is very important for people’s awareness about use of soyabean oil in food. We will be alerted in future about this oil. Thank you very much.

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8 months ago

Guest

Pete Moss

This makes me question why so many want the government controlling everything. If soy bean oil is so bad for me, why does the FDA allow the use of it?

The same can be said for tobacco and trans fats; we’ve known both of these can cause harm for a long time, but they’re still available to buy. I suppose there are healthy foods and not so healthy foods, and it is consumer choice which they go for (and which they can afford).

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3 months ago

Guest

Dejavu

Great article! Thanks!

Where can we get some extra Omega-3s to counterbalance the extra Omega-6 ?

I was buying Sunflower oil in lieu of canola and now need to find avocado oil that isn’t in a spray. Coconut and olive impart too much odd flavor when you are baking a cake! I wonder will avocado oil?

Avocado oil is relatively tasteless, so it might be OK! Or just butter would be a good fit for a cake?

Good sources of omega-3 include oily fish such as herring, sardines, salmon and trout.

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8 months ago

Guest

Rita Wright

Try refined coconut oil it has no taste. It is inhumane the way they market soy products claiming how healthy they are. I feel health food is another racquet of destruction for profit only. Soy also affects the way you think…mood swings, hostility. Also makes you feel weak and fatigued.

I would also stay away from sunflower oil – it is ultra-processed and contains extremely high amounts of omega-6.

Cold-pressed fruit oils (avocado, coconut, olive) are all great.

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10 months ago

Guest

Jessie

Interesting, Chinese have consumed thousands of years soybean oil and they are definitely slimmer than the people from the USA. There are so many dietary, environmental, genetic factors which affect people’s health. it is overgeneralization by saying overweight of US people due to increased consumption of soybean oil. Soybean is not the only contributor to the mentioned diseases. By the way, there is also production procedure for soybean oil called ‘’cold pressing”.

You are correct to say that there are many different factors which contribute to obesity (mainly a bad diet), but soybean oil, sugar, and refined carbohydrates are some of the biggest villains for sure.

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1 year ago

Guest

Shay

Well said Michael and a great article. In most European countries soybean oil can almost never be found in the ingredients. Shocked when I moved to the US and saw that there is soybean oil in almost every loaf of bread that I found!

Thank you for posting this informative and valuable article. I loved the way you would use the subjects and share their individual links. This article is a “keeper” for sure. It’s one that needs to be read several times as to retain the information stated here. God bless.

Slightly better maybe? But most of the concerns remain, and soybean is not really well-suited for use at high heat. I would (ideally) stick to olive oil, and some other oils like coconut oil are very heat-stable too.